Some cannabis products may help with short term pain but side effects are a concern

A review of 25 trials and studies assessing cannabinoids has found that oral synthetic cannabis products with high THC-to-CBD ratios and extracted cannabis products with comparable tetrahydrocannabinol (THC)-to-cannabidiol (CBD) ratios were associated with moderate, short-term chronic pain improvements. However, these products were associated with higher risks for adverse events and few benefits in overall functioning. The findings are published in Annals of Internal Medicine.

Approximately 100 million Americans are living with chronic pain. While opioids are frequently prescribed to manage chronic pain, they demonstrate little affect on pain overall and are associated with significant adverse effects. Cannabinoid products are a potential alternative and can come from multiple sources, including synthetic, extract, or whole plant. The term "cannabinoid" references compounds that are active in cannabis, such as THC and CBD. These compounds have previously demonstrated pain-relief properties that vary depending on the ratio of THC to CBD.

Researchers from Oregon Health & Science University reviewed 18 randomized, placebo-controlled trials, comprising 1,740 participants, and 7 cohort studies, comprising 13,095 participants, to evaluate the benefits and harms of cannabinoids for chronic pain. They found that synthetic products with high THC-to-CBD ratios were associated with moderate improvement in pain severity and response but were also associated with an increased risk for sedation and dizziness.

The authors also found that small improvements in overall function were demonstrated for products with comparable THC-to-CBD ratios, but no improvements were demonstrated for products with high THC-to-CBD ratios. However, they determined that evidence for whole-plant products, CBD, and other cannabinoids was limited by serious imprecision and lack of ability to assess consistency and study methodological limitations. The authors also note that reviewed studies did not evaluate harm outcomes including psychosis, cannabis use disorder, and cognitive deficits, and studies did not include patients who were at higher risk for harms.

An accompanying editorial by authors from the University of Michigan Medical School advises clinicians to be willing to provide compassionate guidance to patients who use cannabis products by using a strategy of pragmatism and knowledge of patient experience, known cannabinoid effects, and harm reduction. The authors highlight that this review can offer information to clinicians on routes of administration, the effects of CBD versus THC, dosing, and potential adverse effects.